Ecosystem Science and Management

Comparison of Prescribed Burning and Mowing to Enhance Greater Sage-Grouse Nesting and Early Brood-Rearing Habitat in the Big Horn Basin, Wyoming

Project Description:Prescribed burning (since the 1990s) and mowing (since 2000) have been extensively used to enhance sagebrush (Artemisia spp.) habitats in the Big Horn Basin of north-central Wyoming.BLM field offices have largely implemented these techniques in an effort to enhance greater sage-grouse (Centrocercus urophasianus) habitats in the Basin.In total, over the 27 years spanning 1980 to 2006, there were 959 prescribed fires and 111 mowing treatments, resulting in 195 km2 burned by prescribed fires and 95 km2 mowed. While fire is recognized as a key factor contributing to the decline of sage-grouse populations, the effects of mowing are not widely known or documented. In spring 2008, we initiated a study to compare the relative value of prescribed burning and mowing to enhance sage-grouse nesting and early brood-rearing habitats within Wyoming big sagebrush (A. t. wyomingensis) communities in the Basin. Through comparing response variables at 30 treated sites to adjacent, untreated control sites, we seek to identify habitat quality through soil, insect, and vegetation parameters in treated sage-grouse nesting and brood-rearing habitats. Our sites were classified by treatment type, soil type, and season and decade of treatment. Our primary objective is to evaluate differences in structural and functional parameters that are known to influence sage-grouse reproduction and survival and ecological function. At each site we measure habitat features that are categorized according to ecological status, grouse forage, soil quality, and vegetation structure, all of which are known to be required by sage-grouse for survival and reproduction. A secondary objective of our study is to evaluate persistence of sage-grouse leks in the Big Horn Basin. We are developing models to predict what factors lead leks to become unoccupied in the Big Horn Basin.